NEWPORT, R.I.—Second-seeded Ivo Karlovic of Croatia used his overpowering serve to beat American Robby Ginepri 7-6 (2), 6-2 Monday in the opening round of the Hall of Fame Tennis Championships.

The 6-foot-11 Karlovic had 17 aces and only two double-faults, winning 92 percent of his first-serve points during breezy conditions on the grass at Newport.

The tournament is held in conjunction with the International Tennis Hall of Fame induction ceremonies. On Saturday, Lindsay Davenport heads a class that includes coach Nick Bollettieri, executive Jane Brown Grimes and broadcaster John Barrett in the contributor category and five-time Paralympic medalist Chantal Vandierendonck.

The Hall of Fame Championships is the only tournament in North America held on grass courts.

Top-seeded John Isner is scheduled to play Tuesday. He's looking for his third title in Newport after winning in 2011-12.

The 35-year old Karlovic, a quarterfinalist in Newport last year, had first serves clocked in the 118-123 mph range in windy conditions.

"You must always adjust with the toss, and I was able to," he said.

After Karlovic went up 5-2 with his second ace of the tiebreaker, Ginepri, a 2003 Newport champion, hit a forehand return into the net and followed with a backhand that sailed wide.

The 31st-ranked Karlovic broke serve in the second and final games of the last set.

"It's always difficult on grass courts," he said. "I was a little lucky on the tiebreak, and I was able to return better and break him twice."